Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 225 AM EST Sat Feb 17 2024 Valid 12Z Sat Feb 17 2024 - 12Z Mon Feb 19 2024 ...Heavy to Excessive Rainfall leading to Flash Flooding possible across much of coastal California... ...Heavy Rainfall likely over much of the Florida Peninsula this weekend... ...Warming trend ensues across midsection of the country... An upper-level disturbance will bring heavy rain to the coasts of northern and central California today. A Slight Risk of Excessive Rainfall (level 2/4) leading to Flash Flooding is in effect between Humboldt and Sonoma Counties where some instability could promote isolated thunderstorm activity. The Pacific moisture responsible for this heavy precipitation will flow into the Trinity and Shasta mountains of northern California, as well as the Sierra Nevada today. Between 6-12 inches of snow are expected for the Sierra while 1-3 feet are likely for the Trinity and Shasta mountains. On Sunday, the previous upper-level energy will propagate into the Intermountain West and Northern Rockies, where it'll generate snow showers for those areas, while a more potent closed low system moves closer to the West Coast. Another round of heavy rainfall is likely to spread across California on Sunday out ahead of a surface low pressure system supported by the aforementioned upper low. Another Slight Risk of Excessive Rainfall is in effect for much of the California coast from Humboldt County down to Ventura County. Heavy rainfall over saturated soils could cause runoff concerns, particularly over Santa Barbara where 2-4 inches of low elevation rain and 4-8 inches in the Transverse Range/other favored terrain will cause Flash Flooding. Another round of 6-12 inches in the Sierra and 1-3 feet over the Trinity and Shasta are also expected on Sunday. Meanwhile, rain and thunderstorms will develop over the Florida Peninsula today along a cold front moving southeast across the state. The front will stall over central Florida on Sunday and an area of low pressure is forecast to develop just off the state's east coast. This surface wave will focus heavy rain and thunderstorms across the peninsula that day. Cool air will spread across the southeastern U.S. today and tomorrow behind the synoptic cold front mentioned above. Milder temperatures build over the Great Plains and Midwest into next week. Lake effect snow likely downwind of the Great Lakes this weekend. Kebede Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php